Carbon-containing monolithic 91asses obtained from organosilsesquioxane gels of the general formula RSiO.sub.3/2 are described in European Patent EP-A-107,943. Due to the low porosity of these gels, molded parts free from defects cannot be produced, except by costly drying processes and even then dimensional reproducibility of the molded parts is not assured.
It is an object of this invention to provide a process for preparing highly porous glass-ceramic molded parts which have carbon atoms linked to silicon atoms, and are free from defects and have reproducible dimensions and high porosity. A further object of the present invention is to provide a process for preparing highly porous glass-ceramic molded parts which are free of defects and have reproducible dimensions in the absence of costly drying and processing methods.